Process of carroting fur and the like and composition therefor



r so Patented Aug. 22, 1939 UNITED STATES PROCESS OF CARROTING FUR- ANDTHE LIKE AND COMPOSITION THEREFOR Constantine F. Fabian, Brookfield,Conn., assignor to The Non-Mercuric CarrotCompany, Danbury, C0nn., acorporation of Connecticut No 1/)tawing.

12 Claims.

This invention relates to carroting processes for fur and the like,employed to give such fur felting properties, particularly for use inhat manufacture.

r In the case of prior carroting processes, it has been the usualpractice to brush the carroting solution on the fur while the latter isstill on the skins, allow it to dry, then either place the skins inpiles or stacks or cut the fur and store the cut fur, and then allow thecarroted fur to remain in that stored state for days, weeks or evenmonths, during which time the carroting compound effects a "working in"so that its full effects are secured. That is to say, such proc- I essesrely in large part on the continued efiect of the carroting after thesolution has been applied and dried and during the period that the furis aging or in storage.

For such agingaction of the carrot, carroting solutions have heretoforeincluded as active agents non-volatile compounds, such as nonvolatileacids, metal catalysts non-volatile salts or non-volatile oxidizers.Thus, in the use of the common nitric acid and mercuric nitratesolution, where the nitric acid is used in relatively low concentrationthe mercuric nitrate is relied on to prolong and complete the carrotingduring the aging. When non-volatile, sulphuric acid is employed as thehydrolyzing agent, the acid acts as a factor in completing the carrotingeffectduring aging, and in such case it has been foundnecessary toprevent destructive action by the acid on the fur during the storage ofthe latter by the presence of compounds which have an inhibiting effect,such as neutral salts of a strong base and a strong acid.

One objection to the heretofore generally prevalent use of the-mercuricnitrate-nitric acid solution is the noxious effect arising from the useof mercury which, as is well knowri, is deleterious to and endangers thehealth of the worker's, both those performing the carroting and thoseengaged in the subsequent steps of hat manufacture.

Another objection to carroting processes as heretofore employed, makinguse of non-volatile carroting agents, has beenthe fact that they resultin deposits on the fur of metal salts or other non-volatile substanceswhich add initially to the weight of the fur, but, due to their watersolubility, these substances are removed in the subsequent washing andother processing of the hats. Accordingly, when the carroted fur isweighed to assign a definite weight to the individual hat bodypreparatory to its formation, a false result is reached since thesubsequently Application November 8, 1938, Serial No. 239,510

formed and processed hat body ilosesxweight in fore, with the use ofcarroting solutions containing such non-volatile, water-solubleingredil0 ents results in-a fur of non-uniform weightawhich adds furtherto the difficulty in securing the finally formed hat bodies of the"intended weight. Furthermore, it is well known that without the agingheretofore referred to; fur *carroted. by 15 processes heretoforeemployed is found to have inadequate felting properties, and such priorprocesses andcarroting compositions have been incapable of adequatelycarroting fur which is required to be used soon after the application ofthe carroting solution and without aging, or storage and which is knownas green fur.

One object of the present invention is to produce adequate feltingproperties in..-the carroted 1 fur, including rapidity in felting,tightness of the felt, and a smooth, firm body in the felted fur.

Another object is to avoid the use of mercury or other metalliccompounds harmful, to the health of the workers. 4

Another object of the invention is to secure the intended weight forhats formed from the carroted fur, through the avoidance of the depositon the fur of metal salts or other non-volatile substances. r

Another object is to make use of a carroting solution substantially freefrom non-volatile carroting agents and of a concentration carefullyselected to provide the optimum condition of carroting effectiveness.Due to the volatility of the solution, this permits the continuance ofthe 4.0 same ideal or optimum carroting effect during the entirecarroting treatment, including both the stage of brushing and the stageof drying. By this means superior felting properties are imparted to thefur since the latter is treated without the necessity of a prolongedstage of aging or storage, which is necessary Where non-volatilecompounds are employed. In the latter case, during' such prolonged stageof drying, the activity and effectiveness of the carrotingegents areemploying a volatile carroting solution, substantially free from metalsalts or other non-volatile carroting agentsjand particularly free frommercury and-the noxious conditions surrounding its use.

In hat manufacture the effectiveness and commercial availability of anycarroting solution is dependent in large measure on the rapidity withwhich the shrinking can be performed in its several stages after the hatbody is formed in the first instance from the oarroted fur.

In hat manufacture as now carried on, the shrinking process commonlyincludes three principal stages-first a so-called wetting down orstarting, next a more vigorous shrinking, and, as a last stage, andusually after the partly shrunk'bodies have been dyed, shrinking tofinal size-and firmness. Each stage of shrinking is commonly carried outin whole or in part on a machine in which the hat body is subjected to akneading action and to the simultaneous application of hot water.

The time consumed in each stage of shrinking is, highly important, notonly because a certain rate of output is commercially essential, butbecause, with properly carroted fur, a more acceptable felt is producedby relatively rapid shrinking, and, in the third stage of shrinking, ifthe timed shrinking is prolonged, the dye-in affected. A certain maximumtime period therefore in which the shrinking must be performed ineach-stage is recognized as essential in the case of any commerciallyoperative or usable carroting process.

In the case of the common mercuric nitratenitric acid solution,relatively low acid concentrations and of a relatively narrow range mustbe employed to bring the shrinking for each of the-shrinking stagesmentioned within the commercially permissible time. Such time, forexample, is exceeded unless the concentration of nitric acid is at leastapproximately 2 70 by weight, but if the acid concentration exceeds approximately 6% such time is again exceeded, the optimum result beingreached with a concentration of approximately from 4 to 5%. Withconcentrations increased above 6%, the time required for shrinking isincreased at a rapidly accelerated rate, so that the use ofaconcentration of nitric acid of even '7 or 8% is inoperative from apracticalv or commercial standpoint. This is true whether or not thesolution is used in the "presence of an oxidizer, such as hydrogenperoxide.

I have found that by employing a volatile hydrolyzing acid, such asnitric acid, in high concentration, and a concentration higher than thatused or practically usable in the mercuric nitratenitric acid solution,and by utilizing in the presence of such high concentration of acid a'volatile oxidizer. such as hydrogen peroxide, an efl'ective carrotingsolution may be had free from mercury and its essential objectionablefeatures and capable of a more rapid shrinking in each of the severalstages of shrinking than can be obtained from the usual mercury carrot.

Any volatile acid having a hydrolyzing action may be employed, such asnitric acid. acctic acid. formic acid, hydrofluoric acid in solution,etc. These acids, howevenshould be employed in relatively highconcentrations. For example, in the case of nitric acid technical acidof approximate ly 63% concentration), which is preferable forconsiderations of expense, convenience and availability, concentrationsare employed having a wide range of from approximately 11 or 12% toapproximately 20% by weight, within which range thcshrinking at each ofthe three stages is effected within the commercially permissible timeperiod.

Using concentrations within the range indicated, an optimum carrotedeffect may be had which reduces the time required for shrinking at eachof the three stages of shrinking to substantially less-than the shortesttime required for acid.

A probable explanation of the effectiveness of this carroting solutionis as follows:

Animal fiber is an amphoteric substance of colloidal nature having basicand acidic functions which may be brought into action only by means ofstrong bases or strong acids respectively. At the isoelectricpoint, orstate of electrical neutrality, the amino groups and carboxyl groups ofthe molecules of these amphoteric substances have interacted to formwhatmay be termed as inner salt which, if undisturbed, remains intact,forming double ionized molecules. To split these molecules and bringthem into a state of maximum chemical activity appears to be animportant function of the carroting treatment.

I have found that the condition of maximum chemical activity for thesemolecules is reached by the use of an acid having a pH value rangingfrom 1.4 to 0.8 lacid'cresol red as indicator), or by the use of analkali having a pH value of approximately 11 La Motte purple asindicator). At all events, under either of these conditions the furacquires the most desirable carroting properties.

Treatment, however, with an alkali is undesirable due to side reactionsand the destruction or impairment of the fur fiber. But, by treatmentwith an acid having a hydrogen ion concentration represented by a rangeof pH 1.4 to pH 0.8 (or one corresponding to a concentration of fromapproximately 11 or 12% to 20% of technical nitric acid at normal orroom temperature) and employing a volatile acid in solution free frognnon-volatile compounds, not only is a pH value furnished in the'firstinstance which is ideal for building up the electrical activity of thefur molecules, but such ideal value is maintained at every stage of thecarroting treatment, i. 0., the stage of brushing and the stage ofdrying.

On the other hand, in the case of a solution including non-volatilecarroting agents. the pH value of the acid hydrolyzcr is constantlyundergoing a change during the drying of the fur, and the pH valuc. ifat any time the ideal 'onc, remains so but for a short interval.

If other volatiliacids such as [11050 mentioned are employed. theconcenlrniion should be such as to llLlVlsubstantially the samehi'drogcnion concentration as the ('oncmlll'utinn ol lllil'lt' acidabove mentioned to ive tlurequir d h,\'drolyzing cl'l'rcl in lhciraction on LllllDl'lOitl'h' substances.

such as proteins. That is to say, a minimum concentration of such acidsshould be used. which is represented by pH 1.2, which corresponds to aconcentration of approximately 12% by weight have a minimumconcentration of approximately vbe employed for the oxidizer.-

" 44%. If formic acid (technical 90%) is used, it

should have a minimum concentration of approximately 38%.

A relatively wide range of concentration may In the case of hydrogenperoxide it is preferably used in the order of from 4 to 8% by weight.Hydrogen peroxide is preferably employed as the volatile oxi-.

dizer due to its availability, oxidizing effect, and

dizers may be employed. Among organic peroxides, for example, there maybe used perox or peroxides obtained by reaction between aldehydes andhydrogen peroxide in ether. On the other hand, organic peracids may beemployed of the type RCOzH such as CHiCOiH.

Where hydrogen peroxide is employed, a small quantity of some stabilizeris preferablyused. In the presence of dust and small metal particleswhich areapt to be deposited on the fur during the processing of theskins prior to carroting, hydrogen peroxide rapidly decomposes,resulting in inadequate and non-uniform oxidation of the fibers. Toprevent such decomposition, a minute quantity of some stabilizingsubstance, such'as urea, citric acid, sodium metaphosphate, sodiumsalicylate, etc., should be employed, these substances being inactive,without carroting effect, and added for the sole purpose of stabilizingthe hydrogen peroxide.

The volatile acid and the volatile oxidizer ould preferably be selectedso that they are zr i capable of reacting one on the other. Forisrample, it is inadvisable to use such compounds chloric acid orperchloric acid for oxidizers which'produce free chlorine, the latterresulting in chlorination of the natural fibers and the weakeningthereof.

A carroting solution prepared as herein de scribed may be brushed on thefur at normal or room temperature and acts promptly following itsapplication to the fur, giving the required carroting effect before ithas disappeared through volatilization, leaving no free acids noroxidizers which must be relied upon to prolong the carroting efiect,leaving no other non-volatile, water-soluble substances on the fur, andrequiring no storage nor aging of the fur to complete the carroting.

The application of the carroting solution to the animal fibers may bemade by brushing or spraying the carroting solution on the fur while thelatter is still on the skins, or cut fur may also be carroted.

The invention will be best understood by the following specific examplesof carroting solutions which may be prepared according to the generalprinciple of the invention and intended each, for

application to the animal fibers while still on the skins. In each ofthe examples, the carroting composition comprises an aqueous solutionconsisting of i100 parts by weight of the, final solution and includingin it the following substances, in the proportions specified. The nitricacid is assumed to :be technical acid approxidrogen peroxide by weight)1 Example 1 j/ 'Partsby y weight Nitric acid 1 5 Hydrogen peroxide "20 WExample '2 Nitricacid 15 Hydrogen peroxide; e s 17 Sodium salicylate0.05

' 4 Example 3' I Nitric acid y 12 Hydrogen peroxide r 17 Urea 0.05Citric acid 0105 WWW Acetic acid (technical 56%) Hydrogen peroxides--.i'17 Sodium metaphosphate 0.005 Sodium salicylate"; 0.05 I mantles wFormlc acidltechnlcal :45 Hydrogen peroxide; 20 Urea" i- 0.05 Citricacid 0.005

This application is a continuation in part of" my prior copendingapplication, Serial No. 212,301, filed June '7, 1938, for Process ofcarroting fur and the like and composition therefor.

Various changes in and departures ,from the embodiment of the carrotingcomposition as herein exemplified may be made, all within the scope ofthe generic invention, it being understood that the matter herein setforth is submitted as illustrative and not in a limiting sense.

I claim:

1. An aqueous carroting solution for treating fur and the likecontaining as its carroting agent a composition consisting of a volatilehydrolyzing acid selected from the group consisting of nitric, formicand acetic acids, and a volatile oxidizer selected from the groupconsisting of hydrogen peroxide, organic peroxides and organic.peraci'ds, the hydrolyzing acid having a hydrogen ion concentrationequivalent at least to that represented by a concentration of 11-12% byweight of nitric acid of approximately-63% technical, and the solutionbeing substantially free fromnon-volatile carroting agents.

2. An aqueous carroting solution for treating fur and the likecontaining as its carroting agent a composition consisting of a volatilehydrolyzing acid selected from the group consisting of nitric, formicand acetic acids, and a volatile oxidizer selected from the groupconsisting of hydrogen peroxide, organic peroxides and organicpera'cids. the hydrolyzing acid having a hydrogen ion concentrationequivalent to that represented by a concentration of between 11 and 20%by weight of nitric acid of approximately 63% technical,

and thesolutlon being substantially free from non-volatile carrotingagents.

-3. An aqueous carroting solution for treating fur and the likecontaining as its carroting agent lmately 63%, and also hydrogenperoxide, said solution being substantially free from non-volatilecarroting agents.

5. The carroting solution defined in claim 2, in which the hydrolyzingacid consists of acetic acid. f 6. The carroting solution defined inclaim 2, in

which the hydrolyzing acid consists of formic acid.

.-7. The process of carroting fur and the like, which comprises treatingthe fur with an aqueous carroting solution containing as its carrotingagent a composition consisting of a volatile hydrolyzing acid selectedfrom the group consisting of nitric, formic and acetic acids, and avolatile oxidizer selected from the group consisting of hydrogenperoxide, organic peroxides and organic 'peracids, the hydrolyzing acidhaving a hydrogen ion concentration equivalent at least to thatrepresented by a concentration of 11-12% by weight of nitric acid ofapproximately 63% technical, the solution being substantially free fromnon-volatile carroting agents, and causing the volatilizatlon of thecarroting solution on the fur.

8. The process of carroting fur and the like, which comprises treatingthe fur with an aqueous carroting solution containing as its carrotingagent a composition consisting of a volatile hydrolyzing acid selectedfrom the group consisting 'of nitric, formic and acetic acids, and avolatile oxidizer selected from the group consisting of hy- 5 drogenperoxide, organic peroxides and organic peracids, the hydrolyzing agenthaving a hydrogen'ion concentration equivalent to that represented by aconcentration of between 11 and 20% by weight of nitric acid ofapproximately 63% concentration of an order represented by approximately11 to by weight of technical acid of approximately 63%, and alsohydrogen peroxide, said solution being substantially free fromnonvolatile carroting agents, and causing the volatilization of thecarroting solution on the fur.

10. The process of carroting fur and the like, which comprises treatingthe fur with an aqueous! carroting solution containing as its carrotingL agent a composition consisting of nitric acid in a L concentration ofan order represented by from 17 to 19% by weight of technical nitricacid of approximately 63%, and also hydrogen peroxide, said solutionbeing substantialy free from non volatile carroting agents, and causingthe volatilization of the carroting solution on the fur.

11. The process defined in claim 8, in which the hydrolyzing acidconsists of acetic acid.

12. The process defined in claim 8, in which the hydrolyzing acidconsists of formic acid.

CONSTANTINE F.FABIAN. M

